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R. P. BARNSTEAD.

ELECTRIC HEATER.

A.=P|.|cAT|oN man Aue. 4. 1919.

1,324,002. Patented Dec. 2,1919.

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ROBERT P. BARNSTEAD, OF BGSTON, MASSACHUSETTS.

ELECTRIC HEATER.

Specification of Letters Patent.

Patented Dec. 2, 1919.

Application filed August 4, 1919. Serial No. 315,351.

To all whom t may concern:

Be it known that I, ROBERT P. BARN- s'rnan, a citizen of the United States, and a resident of Boston, in the county of dutlolk and Commonwealth of Massachusetts, have invented certain new and useful improvements in Electric Heaters, of which the following is a full, clear, and exact specification.

ln a former patent granted to me J une l5, 1915, numbered 1,l1l3,568, I disclosed a means for electrically heating water wherein the receptacle contained several heater units rising from its bottom, the terminals of each heater unit being below the bottom in convenient access for wiring. For fastening the units in place, l show a threaded collar soldered to the lower end of each unit, and adapt-ed to be screwed into water tight engagement with internally threaded sockets inthe bottom.

lVhile this former invention serves the purpose et heating water unobjectionably, it is found to be exceedingly inconvenient to wire the heater unit-s. This is due to the fart that when the threaded collar and attached unit is screwed into place, the terminals of each unit will not, once in a hundred times, lie in a radial plane relative to the receptacle. Consequently, when they are screwed tightly into place and the terminals are found to stand at a wrong angle for convenient wiring, the units must be removed, a thicker or thinner gasket substituted, and the units again screwed in. This has often to be repeated several times for each of the units before the terminals are satisfactorily adjusted, entailing a heavy loss in time and labor, especially in. cases where the water receptacle is provided with two dozen or more of the heater units.

The object of this invention is the construction of an attaching means for the units whereby their terminals can be accurately adjusted without the loss of any appreciable time.

Further, my former method of attachment would often permit of the screw threads becoming so i'iXed in place by corrosion, sedimentary deposits and otherwise, that the units could only be removed by chipping the parts away.

In my present arrangement, the screw threads are completely shi lded from sediment and water, so that the units can always be easily removed for the substitution of fresh ones, without injury or delay.

My invention for this purpose consists in providing each heater unit with a flange adapted to be held in water-tight engagc- 6o ment with a flanged socket in the receptacle socket, the preferable holding means ben a threaded sleeve or annular plug within which the heater terminals have ample room.

ln the drawings forming part of this specification, Figure l is an under view oit a water receptacle showing several heater units applied thereto in accordance with my invention. Fig. 2 is a. vertical section et a 7'!" portieri of the receptacle bottom showil a portion of a unit fastened in place therein. Fig. 8 is a face view of one of the annular plugs. Fig. -l is a sectional elevation of a. part of the receptacle bottom and et a unit in a slightly modified form. Fig. 5 a sectional view of another modilication. ill the views except Fig. l are nearly full size. Fig. t3 is a sectional view of another type ot unit. Y

rlhe heater units l are of well known construction, being externally cylindrical. Soldered about the lower end of each is a collar 2 having a flange 3, as shown in Fig. 2. The receptacle bottom el is preferably S composed of cast metal, and is formed with as many bosses 5 as there are to be heater units, each boss being provided with an internal flange or shoulder 6, and internally threaded between this shoulder and the outside, as shown in Fig. 2.

A gasket, preferably of asbestos T, is introduced into each socket S into close con-V tact with the shoulder 6. Then the heater units l are put in place, with their flanges 3 resting against the gaskets 7, and the ait nular plugs 9 externally threaded to fit the threaded sockets S, are screwed into the latter into light contact with the fianges 3. The heater units l can now be revolved to present their terminals 10 into radial planes as shown in Fig. l, after which the threaded plugs 9 are more forcibly turned to give an immovable grip to the flanges 3 and hence to the heater units. i

For enabling the annular plugs 9 to be thus forcibly manipulated, I provide their outer rim with a polygonal exterior, as ll shown in Figs. l and 3.

The heater units being thus positioned, a

couple of brass or copper strips 12, 13 having' suitably located holes punched or drilled therein and concentrically curved, can be placed over the ends of the terminals and screws 14 introduced through the holes and turned down tightly into the terminals, as shown in Figs. 1 and Q, thus readily and quickly connecting' up all the heater units with the source of electric current.

Instead of the flat flanges 3 and G shown in F ig Q, they may be made a ground joint shown in Fig. 5, or a taper joint shown in Fig. 4. Fig. 5 shows a further modification., that of having the internally threaded sockets 8 made separable from the bottom, and screwed into the latter.

By thus having the gasket, or the taper or ground joint between the interior of the receptacle and the threaded plug 9, no water or sediment can reach said threads and thereby rust and clog the plug against removal.

This electric heater is not confined to heating liquids, as it may be employed equally well for ovens and other chambers to be warmed.

I do not confine myself to the cylindrical heater units 1 shown in Figs. and l, since my connecting means is equally well adapted for the wire form of heater units shown in Fig. 6, and which is especially well adapted for ovens, sterilizers and the like. For this well-known form of heater unit, which consists of a resistance wire passing through a metallic sheath Q1 but suitably insulatedtherefrom, the terminals 22, of the resistance wire are located outside a disk Q1 formed with a cylindrical portion 25 and a flange 3; the ends of the sheath 21 being soldered or otherwise made air-tight in said disk portion. This disk portion 24 has its flange 3 secured in place in the same manner as above described.

Among other advantages obtained through the employment of my attaching means, additional to its ease of removal whereby a pair of pliers are ample tools therefor, are its reliability and certainty against leakage when used in connection with liquid containers, and its capability of supporting the units 1 almost entirely in the liquid, with a consequent greater heating ability.

What I claim is:

An electric heater con'iprising a container having a wall provided with an internally threaded opening and an annular flange at its inner boundary, an electric heater unit having two terminals, an annular flange having said terminals projecting through it and rendered water-tight about said unit, the last-named flange being designed to be pressed inwardly into water-tight engagement with the first named flange, and an externally threaded annulus adapted to be screwed into engagement with the secondnamed flange and to permit said terminals to pass freely through it, whereby the terminals can be freely turned to present them in a desired plane before the externally threaded annulus has been finally tightened up.

In testimony that I claim the foregoing invention, I have hereunto set my hand this 30th day of July, 1919.

ROBERT P. BARNSTEAD. 

